The continuously increasing use of more sophisticated mass production techniques in the assembly of large and relatively complicated machines, vehicles and similar devices comprising a substantially large number of component parts has prompted the development of various types of storage and conveying systems adapted to receive and temporarily store large numbers of component parts or workpieces preparatory to these parts being supplied to associated work stations or production lines where such parts are subjected to various manufacturing operations and are eventually assembled. Heretofore, such storage and conveying systems have consisted of a storage area and a conveying apparatus for picking up the component parts from some location and transferring such parts to a preselected destination in the storage area.
As such component storage systems have become more necessary in mass production applications, the component or material handling equipment incorporated in the storage systems have become continuously more complex, due primarily to the minimum tolerance requirements permitted in the operation of the component conveyor systems in relationship to the associated storage racks or the like in the storage areas, as well as the various problems encountered at the marshalling areas where the component parts were transferred, for example from railroad cars or the like, to the conveyor systems. Also, considerable difficulty has arisen as a result of the need for identifying and coding the various components or workpieces to be stored and the task of conveying the identified products to the conveyor pickup points while maintaining the validity of the loads and relative orientation thereof with relation to the conveyor apparatus.
In order to cope with the above difficulties, it has been necessary to provide and utilize slave pallets onto which the component parts which were to be stored are placed in order to maintain consistent load dimensions with respect to the conveying apparatus, with the result that the conveying apparatus of necessity has consisted of relatively complex equipment for receiving, transporting, delivering and storing such slave pallets and their respective loads. Most recently, such equipment has frequently been in the form of accumulating type indexing conveyors, including automatic turn-tables for effecting 90.degree. or other suitable transfer of the component parts, automatic elevators, and empty pallet return conveyors. Also, such systems have required empty pallet stacking devices, as well as devices for unstacking the empty pallets and delivering them to the marshalling areas preparatory to their receiving new loads to be transferred to the storage complex.
One particular serious problem resulting from the use of the aforementioned type slave pallets with workpiece storage systems has been the necessity of providing means for automatically aligning or "squaring up" the loads with their respective pallets preparatory to the loads being conveyed to the storage area, and means in the form of rejecting stations for automatically rejecting a particular slave pallet and associated load where some predetermined alignment or relative orientation thereof was not achieved. Among other problems resulting from such storage and conveyor systems has been the difficulty in determining what to do with the loads to be stored as they are removed from railroad cars or truck trailers prior to being identified, coded and conveyed to the storage system. Also, many problems have arisen in determining how to transport the stored loads from the storage area to the point of need in the associated production line or the like.
In accordance with the principles of the present invention, a new and improved stacker type storage system is provided which is intended to obviate the aforementioned difficulties encountered in heretofore known systems which employed slave pallets and similar type workpiece transferring apparatus. Generally speaking, the stacker storage system of the present invention is adapted to be operatively associated with a "power and free" or similar type conveying system well known in the art and comprising a plurality of trolley-like component carrier members movable along an overhead track and from which workpieces or components are suspended. Conventionally, a power driven chain or the like is located adjacent the overhead track and is provided with means selectively engageable and disengageable from the carrier members in a predetermined manner to effect the desired movement of the members and component parts suspended therefrom along preselected paths defined by the overhead track.
Generally speaking, the storage system of the present invention comprises a storage complex including a plurality of rows or tiers of storage cubicles and a workpiece transfer assembly adapted to receive workpiece carrier members and the workpiece supported thereby from the associated conveyor system, and convey these carrier members and workpieces to preselected storage cubicles in accordance with some predetermined code or identification, whereby the workpieces may be stored for some predetermined amount of time before being supplied to an associated assembly or production line. At such time as it is desired to utilize the workpieces stored in the cubicles, the present invention functions to retrieve the carrier members and workpieces supported thereby and deliver the same to the associated conveyor system which may then function to selectively deliver the workpieces to their respective work or assembly stations.
By virtue of the principles of the present invention, a considerably more simplified flow of stored materials is provided between the storage complex and their respective points of need or work stations. More importantly, however, the present invention entirely eliminates the need for any conveyor slave pallets as has been required in similar type storage systems heretofore known and used. Accordingly, the many problems attendant the storage and transfer of such slave pallets after they have successfully delivered a workpiece to a work station, and prior to their being provided with successive workpieces, are entirely obviated. Furthermore, through the principles of the present invention, greater operating tolerances are provided within the storage complex and all equipment heretofore required for assuring positive alignment of the loads and their associated slave pallets is eliminated. Also, by virtue of the fact that the present invention readily lends itself to being entirely automated, for example, as by a suitable computerized control system, operation of the storage system of the present invention will find universality of application.